If the sub-feed is literally under the same lugs as the 200A main cable in the meter pan then NO, IT IS NOT OK!

Your post is contradictory though, you say it is under the same lugs, but you also say it is fed from the 200A panel. Which is it?

Not the meter pan but under the 200 amp breaker lugs

So the conductors to the 100 amp garage panel are installed at the top of the 200 amp breaker?

Yes

Not OK for two reasons.

First those lugs aren't designed to have more than one conductor in them. That alone is potentially causing problems.

Second the feeder needs over current protection which is not being provided.

Agree about the matter of the lugs and that alone is enough to fail inspection. Another concern is the length of the run to the garage panel that has no on-premises overcurrent protection.

It needs to be fed from a 2 pole breaker.

Ok I will tell my friend this needs to be fixed. I appreciate it thanks.

I would verify if it is fed with a 4 wire or 3 wire feeder. It needs 2 hots, 1 neutral(insulated) and 1 ground.

Which also leads one to wonder if the circuits in the subpanel have neutral and ground separated...